nim-libp2p/libp2p/protocols/pubsub/floodsub.nim

179 lines
6.3 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2019 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import sequtils, tables, options, sets, strutils
import chronos, chronicles
import pubsub,
pubsubpeer,
rpcmsg,
../../crypto/crypto,
../../connection,
../../peerinfo,
../../peer
logScope:
topic = "FloodSub"
const FloodSubCodec* = "/floodsub/1.0.0"
type
FloodSub* = ref object of PubSub
peers*: Table[string, PubSubPeer] # peerid to peer map
peerTopics*: Table[string, HashSet[string]] # topic to remote peer map
proc sendSubs(f: FloodSub,
peer: PubSubPeer,
topics: seq[string],
subscribe: bool) {.async, gcsafe.} =
## send subscriptions to remote peer
trace "sending subscriptions", peer = peer.id, subscribe = subscribe
var msg: RPCMsg
for t in topics:
trace "sending topic", peer = peer.id, subscribe = subscribe, topicName = t
msg.subscriptions.add(SubOpts(topic: t, subscribe: subscribe))
await peer.send(@[msg])
proc subscribeTopic(f: FloodSub, topic: string, subscribe: bool, peerId: string) {.gcsafe.} =
if not f.peerTopics.contains(topic):
f.peerTopics[topic] = initSet[string]()
if subscribe:
trace "adding subscription for topic", peer = peerId, name = topic
# subscribe the peer to the topic
f.peerTopics[topic].incl(peerId)
else:
trace "removing subscription for topic", peer = peerId, name = topic
# unsubscribe the peer from the topic
f.peerTopics[topic].excl(peerId)
proc rpcHandler(f: FloodSub,
peer: PubSubPeer,
rpcMsgs: seq[RPCMsg]) {.async, gcsafe.} =
## method called by a PubSubPeer every
## time it receives an RPC message
##
## The RPC message might contain subscriptions
## or messages forwarded to this peer
##
trace "processing RPC message", peer = peer.id, msg = rpcMsgs
for m in rpcMsgs: # for all RPC messages
trace "processing message", msg = rpcMsgs
if m.subscriptions.len > 0: # if there are any subscriptions
for s in m.subscriptions: # subscribe/unsubscribe the peer for each topic
let id = peer.id
f.subscribeTopic(s.topic, s.subscribe, id)
# send subscriptions to every peer
for p in f.peers.values:
if p.id != peer.id:
await p.send(@[RPCMsg(subscriptions: m.subscriptions)])
var toSendPeers: HashSet[string] = initSet[string]()
if m.messages.len > 0: # if there are any messages
for msg in m.messages: # for every message
for t in msg.topicIDs: # for every topic in the message
toSendPeers.incl(f.peerTopics[t]) # get all the peers interested in this topic
if f.topics.contains(t): # check that we're subscribed to it
for h in f.topics[t].handler:
await h(t, msg.data) # trigger user provided handler
# forward the message to all peers interested in it
for p in toSendPeers:
if p in f.peers and f.peers[p].id != peer.id:
await f.peers[p].send(@[RPCMsg(messages: m.messages)])
proc handleConn(f: FloodSub,
conn: Connection) {.async, gcsafe.} =
## handle incoming/outgoing connections
##
## this proc will:
## 1) register a new PubSubPeer for the connection
## 2) register a handler with the peer;
## this handler gets called on every rpc message
## that the peer receives
## 3) ask the peer to subscribe us to every topic
## that we're interested in
##
if conn.peerInfo.peerId.isNone:
debug "no valid PeerId for peer"
return
# create new pubsub peer
var peer = newPubSubPeer(conn, proc (peer: PubSubPeer,
msgs: seq[RPCMsg]) {.async, gcsafe.} =
# call floodsub rpc handler
await f.rpcHandler(peer, msgs))
trace "created new pubsub peer", id = peer.id
f.peers[peer.id] = peer
let topics = toSeq(f.topics.keys)
await f.sendSubs(peer, topics, true)
let handlerFut = peer.handle() # spawn peer read loop
handlerFut.addCallback(
proc(udata: pointer = nil) {.gcsafe.} =
trace "pubsub peer handler ended, cleaning up",
peer = conn.peerInfo.peerId.get().pretty
f.peers.del(peer.id)
)
method init(f: FloodSub) =
proc handler(conn: Connection, proto: string) {.async, gcsafe.} =
## main protocol handler that gets triggered on every
## connection for a protocol string
## e.g. ``/floodsub/1.0.0``, etc...
##
await f.handleConn(conn)
f.handler = handler
f.codec = FloodSubCodec
method subscribeToPeer*(f: FloodSub, conn: Connection) {.async, gcsafe.} =
await f.handleConn(conn)
method publish*(f: FloodSub,
topic: string,
data: seq[byte]) {.async, gcsafe.} =
await procCall PubSub(f).publish(topic, data)
trace "about to publish message on topic", name = topic, data = data.toHex()
if data.len > 0 and topic.len > 0:
let msg = makeMessage(f.peerInfo.peerId.get(), data, topic)
if topic in f.peerTopics:
trace "publishing on topic", name = topic
for p in f.peerTopics[topic]:
trace "publishing message", name = topic, peer = p, data = data
await f.peers[p].send(@[RPCMsg(messages: @[msg])])
method subscribe*(f: FloodSub,
topic: string,
handler: TopicHandler) {.async, gcsafe.} =
await procCall PubSub(f).subscribe(topic, handler)
f.subscribeTopic(topic, true, f.peerInfo.peerId.get().pretty)
for p in f.peers.values:
await f.sendSubs(p, @[topic], true)
method unsubscribe*(f: FloodSub,
topics: seq[TopicPair]) {.async, gcsafe.} =
await procCall PubSub(f).unsubscribe(topics)
for p in f.peers.values:
await f.sendSubs(p, topics.mapIt(it.topic).deduplicate(), false)
method initPubSub*(f: FloodSub) =
f.peers = initTable[string, PubSubPeer]()
f.topics = initTable[string, Topic]()
f.peerTopics = initTable[string, HashSet[string]]()
f.init()